#include<stdio.h>
#include<iostream>
#include<math.h>
double dist(double x1,double x2,double y1,double y2){
	double x=pow(x2-x1,2),y=pow(y2-y1,2);
	return sqrt(x+y);
}
using namespace std;
int main(){
	double x1,x2,x3,y1,y2,y3;
	cin>>x1>>y1>>x2>>y2>>x3>>y3;
	printf("%.2f",dist(x1,x2,y1,y2)+dist(x1,x3,y1,y3)+dist(x2,x3,y2,y3));
	return 0;
}

